Effect of interchain coupling on a biexciton in organic polymers

• 来源期刊: 中国物理B（英文版）
• 关键词: biexciton polymers binding energy
• 年，卷（期）: 2009,（7）
• 页码范围: 2961-2966
• 页数: 6页
• 语种: 英文

摘要

The effect of interchain coupling on the formation and the stability of a biexciton is studied in poly (p-phenylene vinylene) chains in the framework of the tight-binding approach. We obtain an intrachain exciton and biexciton as well as an interchain exciton and biexciton through a double-photon excitation. It is found that a biexciton is energetically favourable to two single excitons even when there exists an interchain coupling. There is a turnover value t⊥C of the interchain coupling for the formation of a biexciton, beyond which two excitons are combined into one biexciton. The binding energy of a biexciton is calculated to decrease with the increase of interchain coupling, which indicates that a biexciton is relatively stable in polymers with a weak interchain coupling. The conclusion is consistent with the experimental observations. In addition, a suggestion about how to improve the yielding efficiency or the formation of biexcitons in actual applications is given.